Improvement in annealing hollow iron-ware



UNITED STATES PATENT OFFICE.

DAVID STUART, 6F PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN ANNEALING HOLLOW IRON-WARE.

Specification forming part of LettersPatent No. 10,05l, dated September 27, 1853.

v of Pennsylvania, have invented a new and Improved Mode of Annealiu g Hollow Iron-Ware; and I do hereby declare that the following is a full and exact description thereof.

The nature of my invention consists in covering the inside of iron hollow ware with a paste made of a composition to exclude the air, and which resists the influence of the heat. When the hollow ware is properly prepared in this manner it is placed in the oven and heated tocherry-red, whereby the chili is taken out of the surface and rendered so soft that it can be turned bright in a turning-lathe, or otherwise, preparatory to tinning.

To enable others skilled in the art to make and use n1y invention,I will proceed to describe its construction and operation.

In the old process of annealing or softening iron hollow ware the ovens were built of brick, of a large size, with fines all round them, and

theavare was packed into this oven with charorder to exclude the air. A strong fire was kept up on the ware for forty-eight hours, and it took about. six days to tilt and empty an oven. Another plan-more expensive, but adopted for sake of saving time-is building a large oven in such a shapeas to allow cars to be put n and taken out on railroads. Thecars have large cast-iron pans onthem, five feet high by three feet wide, in which the hollow ware is packed with charcoal-dust or line coke. They are heated up in the oven twenty-four hours, then taken out and allowed to cool, emptied, and filled up, &c. The pans weigh over half a ton and burn out very fast, being very expensive, besides the other outlays for labor.

To avoid these difficulties and to save time and expense I invented a new and useful mode of annealing iron hollow ware, which consists in building ovens, as hereinafter described, holding about sixtypieces of iron hollow ware or more, as the case may be. Before I place the hollow ware in said even I coat the inside of each piecewith a composition or compound, which excludes the air from the surface to which it has been applied, and which resists the influence ofheat.

The composition may be soapstone-dust and carbon. The more carbon there is in the mixture for coating the better. This composition is mixed with water to about the thickness of rich cream, and pour from half a pint to two quarts, according to they size of the article to be annealed, into the article to be annealed. Work the compound around the inside of the pot or boiler till completely covered on the inside surface. Then I place it, mouth downward, on awire shelf or other similar fixture with open bars, to allow the compound to drain oli'. The pot thus coated is then placed in the oven with titty or sixty others, all prepared in the same way and heated to a cherryred, which takes from twenty to thirty minutes, according tothe heat of the oven. No more ware should,be coated in one day than is int can be turned out bright, by means of a lathe or otherwise, preparatory to tinning.

In constructing my oven I build up a heavy mass of brick-work, which forms the floor, upon which the iron hollow ware is placed to be annealed. The fire-place is made lower than the door, and the whole oven is arched over with firebricks. I make a large door for the larger ware to be placed in the oven, and a small door for the hollow ware of lesser dimen-' sions. I use an ordinary flue, with a damper to regulate the heat. The even may be built in various ways, the form and character of the oven not being essential to my claim.

What 1 claim as my invention and improvement in annealing hollow ware is- The process hercinabove, substantially as described, the same consisting in coating thearticlcs, in the manner set forth, with some composition that will resist heat and exclude air from the surface, and heating the articles so coated in an even about the length of time specified.

DAVID STUART.

Witnesses:

' G. A. RICHARDS, WM. BENNETT. 

